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The XFX ATX Black Edition 850W is particularly aimed at enthusiast gamers. It can deliver power to a range of system components including mid- to high-performance PCI Express graphics cards.

In specific tests, the XFX Black Edition achieved 100 per cent of the manufacturer's claimed performance based on real world scenarios involving the most commonly used 12 volt rails.

In terms of total efficiency, the XFX PSU couldn't quite match the Cooler Master Silent Pro Gold 800W, but is still marginally better than the NesteQ Xzero 700W.

However, it gained points in terms of standby efficiency, being one of the best performers in its range. So if you're looking for an efficient sleeper, we could have a winner for you.

In use, it was clear the PSU produced considerably more noise when compared to similar power supplies like the Scythe Stronger 700W and the Cool Master Silent Pro Gold 800W, making it loudest under test.

To compensate for the extra noise, the fan did at least perform well, helping keep the PC cooler on the inside, however the cables were warm to the touch during high loads. The tested rails were all within the ATX specified tolerances, but the Black Edition produced a fair amount of jitter at a 75 per cent voltage reading.

The XFX ATX Black Edition 850W casing is a plain black affair that houses an eye-catching candy-green fan, which is enclosed in a fan grate inspired by a spider's web, while the rear hot-air vent is an industrial-looking gate design.

Generally, we're impressed by the build quality of the Black Edition, being well engineered all round. It's slightly bigger than the average sized PSU with dimensions of 170 x 86 x 150mm. It is though fairly heavy, weighing in at a 2.702kg. The manufacturers' stated AC power input is 100-240V AC,12-6A 50/60Hz.